Old School RCA WO-91C Oscilloscope Restoration.

[@ScoutCrafter]

Awesome scope! It works too! 😃👍

[@hestheMaster]

Fantastic find and repair to get it working at least. WO-91A was from 1956 with a small upgrade to WO-91B in 1960. Finally they upgraded the power supply circuit to solid state in 1967 to the WO-91C. Back then this was a back up oscy in a repair shop for just specifically quick checking radios and some circuits in televisions. Surprised they didn't upgrade the connector from the old style Switchcraft 2501F to BNC on the front by then, but you can do that when you do fully restore it. Look forward to an eventual part 2. Thanks Fred. Steve from IL

[@ko2fjb]

Well I still have a ways to go to get it working the way it should but at least there is a trace on the scope. Its interesting that there are a lot of schematics on the internet for the 91A & B but none for the C version. It was easy to trace the wiring once i realized the replaced the rectifier tubes with Silicon diodes. Yes I will be replacing the old switchcraft with a BNC at some point. Next its on to ordering all the caps I will need and resistors if necessary. Well its Christmas Eve and the hobbies are on hold until the 26th so part 2 will be delayed.

[@W1TEA]

Yas!! Thanks for the vid!

[@Dennis-uc2gm]

Reminds me of the EICO 460 I assembled winter of 1974 while still in High School. 👍

[@alanuk8677]

Nice looking Scope Fred, should clean up well. I recently acquired a Heathkit OS-2 in lovely condition, only needed a squirt of contact cleaner and it's working like new!

[@robbo6460]

Excellent video Fred. I love the old stuff.

[@ko2fjb]

Glad you enjoyed it! More to come.

[@ko2fjb]

@tonysvets pull the Oscilloscope out and restore it in memory of your father in-law.